1. Field of Invention
The present invention relates to a cooling apparatus of an internal combustion engine including an insert inserted into a water jacket of a cylinder block of the engine, and more particularly, relates to a structure for fixing the insert to the cylinder block.
2. Description of Related Art
In an internal combustion engine, a water jacket is formed around cylinder bores in a cylinder block, and engine cooling water is caused to flow in the water jacket to cool the engine which is heated due to combustion and sliding of a piston. A temperature of a cylinder bore wall is likely to be higher at an upper portion of the cylinder bore wall than at a lower portion of the cylinder bore wall. Therefore, if the cooling water is caused to flow uniformly at an upper portion and a lower portion of the water jacket for preventing the temperature of the upper portion of the cylinder bore wall from being too high, the lower portion of the cylinder bore will be over-cooled, resulting in an increase in a friction loss generated in the sliding of the piston with the cylinder bore.
In order to improve a temperature distribution in the cylinder bore wall, Japanese Utility Model Publication SHO 57-43338 discloses that an insert is disposed in a water jacket. By providing the insert in the water jacket, a heat removed from the cylinder bore wall can be controlled. More particularly, at a portion where the insert is provided, a flow amount is decreased and the temperature of the cylinder bore wall is maintained high (i.e., less of a cooling effect takes place). By the heat control, the temperature distribution of the cylinder bore wall is improved.
In a closed deck-type cylinder block, the insert can be inserted into and mounted in the water jacket through a water hole formed in an upper deck of the cylinder block.
In the engine having the insert in the water jacket, if the insert is not fixed relative to the cylinder block properly, the insert may be moved and dislocated from a normal position when receiving a pressure from the cooling water. If dislocated, the insert cannot perform a normal temperature control and may block the water hole.
An object of the invention is to provide a cooling apparatus of an internal combustion engine capable of preventing an insert disposed in a water jacket from being dislocated from a normal position.
The above object can be performed by the following cooling apparatus of an internal combustion engine according to aspects of the present invention.
A cooling apparatus of an internal combustion engine according to one aspect of the invention includes a closed deck-type cylinder block and an insert. The closed deck-type cylinder block has a water jacket for causing engine cooling water to flow therein to cool the engine, and an upper deck including a water hole formed therein for causing the cooling water flow therethrough and a water hole portion surrounding the water hole. The insert is disposed in the water jacket and is inserted into the water jacket through the water hole. The insert is fixed relative to the cylinder block at the water hole portion such that the insert is fixed in position in a flow direction of the cooling water.
According to one embodiment, the insert includes a spring mechanism formed therein for fixing the insert to the cylinder block by a reaction force of the spring mechanism. This avoids a specialized machining of the cylinder block.
According to one embodiment, a pad is provided in a clearance between the water hole portion and the insert, for fixing the insert to the cylinder block. This also avoids a specialized machining of the cylinder block.
According to one embodiment, a clip is provided that engages with the water hole portion and the insert so as to fix the insert to the cylinder block.
According to one embodiment, the cylinder block includes a groove formed in the water hole portion of the upper deck, and the insert has a key formed therein and fitted in the groove so as to fix the insert to the cylinder block.
A cooling apparatus of an internal combustion engine according to another aspect of the invention includes a closed deck-type cylinder block and an insert, wherein the closed deck-type cylinder block has a water jacket for causing engine cooling water to flow therein to cool the engine and a water jacket wall surrounding the water jacket, and an upper deck including a water hole formed therein for causing the cooling water to flow therethrough. The insert is disposed in the water jacket and is inserted into the water jacket through the water hole. A stopper for preventing the insert from moving downstream in a flow direction of the cooling water is formed to the water jacket wall, and the insert engages the stopper such that the insert is fixed in position in the flow direction of the cooling water.
According to one embodiment, the stopper is a protrusion formed in at least one of a bottom wall portion and an outer side wall portion of the water jacket wall.
According to one embodiment, the stopper is an extension extending from a cylinder head mounted to the cylinder block into the water jacket.
According to one embodiment, the stopper is an extension extending from a cylinder head gasket mounted to the cylinder block into the water jacket.
According to one embodiment, the stopper is a protrusion protruding from a tight plug mounted to the cylinder block into the water jacket.
According to one embodiment, the stopper is a chaplet used in the manufacture of the cylinder block, and which remains in the water jacket.
A cooling apparatus of an internal combustion engine according to one aspect of the invention includes a closed deck-type cylinder block and an insert, wherein the closed deck-type cylinder block has a water jacket for causing engine cooling water to flow therein to cool the engine, and an upper deck including a water hole formed therein for causing the cooling water to flow therethrough. The insert is disposed in the water jacket and is inserted into the water jacket through the water hole. The insert includes an upstream portion having a streamline configuration.
By fixing the insert relative to the cylinder block at the water hole portion, the insert is prevented from being dislocated from its normal position when receiving a pressure from the cooling water, while feasibility of mounting the insert into the water jacket is maintained.
By causing the insert to contact the stopper formed to the water jacket wall, the insert is prevented from being dislocated from its normal position when receiving a pressure from the cooling water, while feasibility of mounting the insert into the water jacket is maintained.
By forming the insert to have an upstream portion having a streamline configuration, the pressure acting on the insert from the cooling water is minimized. As a result, the insert is prevented from being dislocated from its normal position.